Page 80 - General and Inorganic Chemistry for Advanced Secondary Schools Students Book Form Five and Six

Biology for Secondary Schools

of high concentration to a region Advantage of amoeba
of low concentration. When there (a) Amoeba are commonly used in
is a high concentration of urea or laboratories to study cell structure
ammonia in the amoeba, these and function.
substances flow out of the amoeba (b) Amoeba are important decomposers
FOR ONLINE READING ONLY
into the surrounding water. in aquatic environments, feeding on
(g) In amoeba, oxygen and carbon organic particles in the water.
dioxide gases are exchanged by
diffusion. Disadvantage of amoeba
(h) They are unicellular organisms. Some species of Amoeba cause
(i) They reproduce asexually by binary diseases. For example, Entamoeba
fission, as shown in Figure 5.9. histolytica causes amoebic dysentery
in humans and Entamoeba gingivalis
cause teeth and gum diseases.

Exercise 5.3

(a) (b) 1. Imagine you are a scientist studying
micro-organisms in a pond
ecosystem. While examining a water
sample under a microscope, you
(c) (d) come across a single-celled organism
with unique appearance. Describe the
characteristics you would look for
Figure 5.9: Binary fission in amoeba to determine whether this organism
(a) mother cell (b) mother cell nucleus is a protoctists.
divides (c) mother cell cytoplasm divides
(d) two new daughter cells 2. You are a medical researcher
investigating an outbreak of amoebic
dysentery in a community. You have
Task 5.5
collected samples from patients and
Use reliable internet sources to view identified the causative organism

simulations and videos showing: using a microscope. Describe the
(a) Movement in amoeba key characteristics of this organism
(b) Feeding in amoeba that would help you confirm that the
organism is the one responsible for
(c) Asexual reproduction (binary causing amoebic dysentery.
fission) in amoeba
3. Explain the advantages of amoeba.

74 Student’s Book Form One Student’s Book Form One

15/10/2024 09:24:30
Biology FORM 1 new.indd 74
Biology FORM 1 new.indd 74 15/10/2024 09:24:30